NEW ORLEANS – Concerned the Superdome might not be able to handle the energy needed for its first Super Bowl since Hurricane Katrina, officials spent hundreds of thousands of dollars on upgrades to decayed utility lines, according to documents obtained by The Associated Press.

The improvements apparently weren't enough, however, to prevent an embarrassing and puzzling 34-minute power outage during the third quarter of the game between the Baltimore Ravens and San Francisco 49ers on Sunday.

Two days later, officials still had not pinpointed the cause of the outage. The Superdome's management company, SMG, and the utility that supplies the stadium, Entergy New Orleans, announced Tuesday that they would hire outside experts to investigate.